A 3-dimensional (3D) ultrasound diagnostic system is a medical equipment for providing clinical information such as spatial information, anatomical information and the like, which cannot be provided from a conventional 2-dimensional image. The 3D ultrasound diagnostic system acquires volume data from signals received from a target object through a probe, and performs a scan conversion process for the acquired volume data. A 3D ultrasound image of the target object is displayed on a display device such as a monitor, a screen or the like by performing a rendering process upon images obtained from the scan-converted data. This is so that a user can obtain clinical information of the target object.
As is well-known in the art, the probe typically has a plurality of transducers, wherein the respective timing of inputting pulse signals to each transducer is appropriately delayed. This is so that a focal ultrasound beam is transmitted into the target object along a transmit scan line. Each transducer receives echo signals reflected from a focal point on the transmit scan line in a different reception time and converts the echo signal to reception signals of an electrical signal. The reception signals are transmitted to a beam former. The reception signals are appropriately delayed, wherein the delayed reception signals are summed in the beam former. This is so that the reception focal beam representing an energy level reflected from the focal point on the transmit scan line is outputted. Until a 2D slice image of the target object formed by the reception focal beams for a plurality of scan lines is generated, the above process is repeatedly carried out.
A volume data acquisition unit outputs the volume data by synthesizing 2D ultrasound images, which represent sectional planes of the target object, inputted from the beam former. The volume data are generated from signals reflected from the target object existing in a 3D space and defined in torus coordinates. Therefore, in order to perform a rendering process for the volume data in a display device having Cartesian coordinates (e.g., monitor, screen and the like), the scan conversion for performing coordinate conversion of the volume data is required. The scan conversion is implemented in a scan converter.
Scan-converted volume data in the scan converter are rendered through a typical volume rendering process so that the 3D ultrasound image is displayed. The user obtains clinical information of the target object through the 3D ultrasound image displayed on the display device.
The 3D ultrasound diagnostic system is primarily utilized for displaying a shape of a fetus with the 3D ultrasound image in the fields of obstetrics and gynecology. After acquiring volume data by scanning an abdominal region of a pregnant woman, the volume rendering process is performed upon the acquired volume data. This is so that the shape of the fetus can be displayed with the 3D ultrasound image. However, since the volume data includes mixed data of uterus tissue, adipose tissue, amniotic fluid, floating matters and the fetus, if the rendering process is directly applied to the volume data, it is difficult to clearly display the shape of the fetus with the 3D ultrasound image. Therefore, in order to display the shape of the fetus with the 3D ultrasound image, it is required to segment the fetus region from neighboring regions such as the amniotic fluid and the like.
Accordingly, through the use of external interface devices (e.g., a mouse, a keyboard and the like) connected to the 3D ultrasound diagnostic system, a region of interest (ROI) box enclosing the shape of a fetus in a 2D ultrasound image, which is displayed on the display device, can be generated as illustrated in FIG. 1A. Thereafter, a final ROI box is generated by finely operating the external interfaces as illustrated in FIG. 1B. The volume data existing in a contour detected from an image in the ROI box are rendered such that the 3D ultrasound image of the fetus can be displayed.
However, since the generation of ROI box generation and the detection of contour for the target object image are manually operated by the user in the 3D ultrasound diagnostic system, the quality of the finally displayed 3D ultrasound image depends on the expertise of the user. That is, the size of the ROI box is not consistent according to the user generating the ROI box. As such, there is often a problem since a desired 3D ultrasound image of the target object cannot be accurately displayed.
Also, even if the user is an expert, there is a problem in that it takes a long working time to generate the ROI box and detect the contour of the target object image from the 2D ultrasound image. This is because the user generates the ROI box directly on the 2D ultrasound image. Moreover, if the size of the ROI box is not accurate for the desired 3D ultrasound image of the target object, then there is a problem in that an error may be generated in the volume data rendering process or the contour detection process of the target object in the ROI box.